1. Field
Example embodiments relate to light-emitting devices (LEDs) and methods of manufacturing the same.
2. Description of the Related Art
Semiconductor light-emitting devices (LEDs) are highly efficient and environment-friendly light sources that are used in various devices such as displays, optical communication devices, vehicles, and/or general lamps. Currently, as a result of the development of white light LEDs, LED technology is also found in general purpose lamps. A white light LED may be formed by combining, for example, a blue or ultraviolet LED and a phosphor, or combining red, green, and blue LEDs.
A blue or ultraviolet LED that is a main component of a white light LED is formed by using a gallium nitride (GaN)-based compound semiconductor. A GaN-based compound semiconductor has a wide bandgap and may emit light of almost all wavelengths from ultraviolet light to visual light, according to the composition of a nitride.
Typically, a thin film-type GaN LED is formed by growing a GaN thin film on a sapphire (Al2O3) substrate. However, if a GaN-based compound semiconductor is grown on a sapphire substrate in the form of a thin film, light emitting efficiency is reduced due to a mismatch in lattice constant or a difference in thermal expansion coefficient, and large area growth is difficult, and thus manufacturing costs may increase. Also, when a laser lift-off (LLO) process is performed to remove a sapphire substrate after growing a GaN thin film, the output of light may be reduced due to laser impact.
In order to increase a manufacturing yield and reduce manufacturing costs of LEDs, a method of manufacturing a GaN LED using a silicon substrate is currently suggested. A silicon substrate having a wafer of a diameter greater than 12 inches may exhibit less warping in a high temperature process as compared to a sapphire substrate. Also, if a silicon substrate is used, after growing a GaN thin film, the silicon substrate may be removed without performing an LLO process and thus the output of light may not be reduced.